Social networks such as Facebook, Twitter. Google+ are operated by building links or connections among users based on their social relationships. Recently, with the popularity of portable electronic devices increasing, it has become increasingly convenient and easier to obtain the location information associated with a user. A desire to be able to search through the social network for any other registered users that share the same interests has arisen. For instance, when a user needs a service, he or she may want to be able to directly search on the associated social network and obtain information on other users on the social network providing the service.